1. Field
One or more embodiments described herein relate to an electrostatic chuck assembly, a semiconductor manufacturing apparatus having an electrostatic chuck assembly, and a method for measuring the temperature of an electrostatic chuck.
2. Description of the Related Art
Semiconductor, display, and other integrated circuit devices are manufactured by performing various processes (e.g., deposition, etch, photolithography, ion injection processes) on a substrate or other object. A semiconductor etch process may be performed by an apparatus which includes a gas supply unit connected to a process chamber. The gas supply unit provides a process gas to the process chamber for etching a substrate, which is held in position by an electrostatic chuck (ESC).
During this process, a temperature difference may be occur at various locations of the substrate. This temperature difference may degrade the quality of the integrated circuit device.
In an attempt to address this issue, a sensor may measure the temperature of the ESC or substrate. Various control operations may then be performed to reduce the temperature difference. However, when the sensor is installed at one or a few positions on the ESC, the temperature differences at various regions of the ESC may not be accurately measured. For example, when the number of temperature sensors is relatively few, the measured temperature may not represent the temperature of the ESC or substrate. Thus, a temperature distribution defect in the ESC may not be detected. Accordingly, accurate temperature control of the ESC or substrate is difficult.
Another approach involves measuring temperature in multiple zones of an ESC and performing temperature control of individual zones based on the temperature measurement. The temperature measurement of an individual zone may be used as a basis for controlling the temperature of each zone of the ESC. However, the number of temperature sensors increases linearly with the number of individual zones. This increase may add cost and complexity to the process as well as threaten the reliability of the ESC.
In an attempt solve this problem, a method for applying a temperature sensor to a single optical fiber has been proposed in order to measure temperatures at a plurality of positions. One example of such a sensor is a fiber Bragg grating (FBG) sensor. However, increases in the temperature measurement range of the sensor may produce a wide wavelength range for measuring temperature. Consequently, a certain distance must exist between measured wavelengths in an attempt to remove interference between neighboring wavelengths.
When this distance is not secured, interference may make it difficult to check which wavelength is a temperature signal at a corresponding position to be measured. This distance may also reduce the number of FBGs that is able to be provided on a single optical fiber. Thus, a large number of optical fibers may be used to measure temperature at one or various positions, which increases costs and complexity and degrades reliability.